ok here i thought about something else that makes me go "wow". i bought a 10inch dobsonian telescope for astronomy only 1 year ago. soon i figured out it also works great for plane spotting. i live around karlsruhe, germany, its rather busy airspace. i also have a pair of cheap 20x80 astro-binoculars that also are great for spotting, you dont even have to prepare anything, just open my balcony door, pop out the bino, check out the aircraft and go back inside.
now the coolest thing is this: theres a website called "flightradar24", it gives you the exact location, altitude, speed, squawk and registration number, and even shows a picture of every aircraft in europe in realtime !... so on a lazy afternoon i can check out those aircraft in the sky, see wether its a 737, a business jet or something else, then go to that website and check out where its going and see all the details. everything without paying a cent. now thats awesome.
i also can check on flightradar24 what gonna approach in the next 30 seconds and than try to spot the aircraft. in the night u can see the cabin lights ! most aircraft fly high altitude (8K to 12K meters) but some who land in stuttgart or baden-baden come in rather low at about FL 20. on a good day i have visibility of 50 to 100km !
cheers MB